Section 26(1) says:
Improvement and adaptation of land for allotments.
(1)The council of a borough, urban district, or parish may improve any land acquired by them for allotments and adapt the same for letting in allotments, by draining, fencing, and dividing the same, acquiring approaches, making roads and otherwise, as they think fit, and may from time to time do such things as may be necessary for maintaining such drains, fences, approaches, and roads, or otherwise for maintaining the allotments in a proper condition.
(2)The council may also adapt the land for allotments by erecting buildings and making adaptations of existing buildings, but so that not more than one dwelling-house shall be erected for occupation with any one allotment; and no dwelling-house shall be erected for occupation with any allotment of less than one acre.
I can't see that part 2 applies. As I read it, part 1 gives a council powers to maintain fences etc, but there is no obligation for the council to use these powers if it chooses not to. The key word is 'may'.